Drugs For Treating Asthma Flashcards
What is asthma?
- chronic inflammatory disease of the airway
- results in obstruction of the airways from bronchoconstriction, edema, and excessive mucus production
Why are NSAIDs typically ineffective in treating inflammation in repiratory system, but corticosteroids are?
Asthma is caused by leukotrienes which is a separate branch off of arachidonic acid. Corticosteroids act on phospholipase A2, whereas NSAIDs inhibit later on in the process to COX.
Name some factors that can precipitate an asthma exacerbation:
- pet allergens
- dust mites
- fungal spores
- infection
- tobacco smoke
- pollen
- chemical exposure
- comorbid conditions
- cold temperatures
- NSAIDs
- exercise
What is EIB?
- exercise induced bronchospasm
- can be a symptom of asthma, but can have bronchospasm and no asthma
- if it only happens in exercise, it’s usually EIB
What is NSAID induced asthma?
- NSAIDs or aspirin can trigger asthma in those that have severe asthma
- less likely in those with mild or moderate asthma
What is bronchospasm?
- reversible airway obstruction caused by spasm of the smooth muscles of the bronchial walls
- non inflammatory, meaning an anti-inflammatory will not help.
What are the 2 categories of asthma/EIB medications when categorized by therapeutic intention?
- quick-relief therapy: “rescue” medications, used for acute symptoms
- long-term therapy: decrease chronic inflammation, decrease frequency of acute attacks
What are the 2 categories of asthma/EIB medications when categorized by pharmacological activity?
- bronchodilators: relax bronchial smooth muscle, open airways
- anti-inflammatory drugs: decrease chronic inflammation
How are quick-relief drugs used?
- treat symptoms in an acute attack
- prevent an imminent attack
- taken when needed, not on a routine basis
- can also be taken prophylactically before exercise if EIB
- every asthma patient should have a quick-relief drug available
Name 3 quick-relief drugs:
- short acting beta2 agonists (SABA)
- anticholinergics
- systemic corticosteroids
What do Beta 1 and Beta 2 do?
- Beta 1: receptors found in heart and kidneys (can have impact on BP and blood volume). Can be considered a performance enhancing drug.
- Beta 2: dilating bronchioles
Most SABA are made up of….
A mix of Beta 1 and Beta 2.
How do short acting beta2 agonists work? What are some examples of it?
- rapid onset (5 min or less)
- short duration (up to 6 hours)
- results in broncodilation
- if needing quick-relief drugs daily, they are not being managed well and need long term medications. Tolerance can be developed to both.
- ex. Albuterol/Salbutamol - Albuterol (Ventilin) most common
Side effects of short acting beta2 agonists (SABA):
Most effects are local because of inhalation, less risk of the side effects below:
- short term muscle tremor (can effect sport performance)
- hyperglycaemia
How do anticholinergics work? Give an example.
- inhibit cholinergic receptors of the parasympathetic nervous system
- not commonly used in asthma treatment
- specifically blocks the action of neurotransmitter acetylcholine. Blocks mucus production and causes broncodilation
- Can be used for asthma (not as common) and EIB. Not nearly as effective as SABA
- ipratropium - often used in combination with SABA
How does systemic corticosteroids for asthma work?
- typically oral administration
- most commonly prednisone
- short course
- risks/adverse effects
Name 4 long-term therapies for asthma.
- inhaled corticosteroids
- long acting beta agonists (LABA)
- mast cell stabilizers
- leukotriene modifiers
What are the purposes of long-term therapies for asthma?
- reduce the incidence of acute attacks
- scheduled medication therapy
Inhaled corticosteroids are commonly utilized with ______ or ______. Why?
- SABA
- LABA
- SABA or LABA will open up bronchioles and allows corticosteroids to pass through and anti-inflammatory effect gets to where it needs to go.
How do inhaled corticosteroids work?
- mainstay of long-term therapy
- reduces the frequency and severity of acute attacks
- improves control of nocturnal asthma
- decreases EIB
How can inhaled corticosteroids be adjusted with increased asthma severity?
- increase dose
- add LABA
Side effects of inhaled corticosteroids:
- local adverse effects. Side effects are limited due to inhaled nature.
- hoarseness, cough, thrush
- minimized by use of a spacer
- rinse mouth after each use
What is thrush? How can it be avoided?
- yeast infection in mouth or pharynx
- can be common with corticosteroid inhaler
- rinse mouth with water after taking corticosteroid inhaler to avoid thrush
How do long acting beta agonists (LABA) work?
- inhaled bronchodilators
- can also come in extended-release oral tablets (uses SABA in extended release pill form to make it LABA. More substantial side effects of SABA)
- slower onset than SABA
- beneficial effects include decreasing rescue inhaler use, decreasing nocturnal asthma
How should LABA be used?
- should not be used alone as the only long-term control medication
- can be added to inhaled corticosteroid regimen
- susceptible to developing tolerance to these.
Give an example of a LABA.
Salmeterol
How do mast cell stabilizers work?
- anti-inflammatory agents
- inhibit release of inflammatory mediators from mast cells
- not as effective as corticosteroids
- not preferred asthma treatment
Side effects of mast cell stabilizers:
- low incidence of adverse effects
- sometimes headaches, throat irritation, bad taste in mouth
Give an example of a mast cell stabilizer.
Cromolyn
How do leukotriene modifiers work?
- oral anti-inflammatory medication
- inhibit the synthesis or the activity of leukotrienes
- variable effectiveness
- often used in combination with inhaled corticosteroids
- not everyone will respond to this. It can be very effective, but is not commonly tried unless other therapies don’t work
- relatively few adverse effects
How do inhalers help with delivering medication?
- local delivery to site of action. Limits systemic side effects
- better pharmacokinetic parameters
- avoids GI absorption
- avoids first-pass effect
- avoids systemic distribution
Name the big issue with use of inhalers.
Proper technique is important to effective therapy
Name the advantages of using a metered dose inhaler.
- delivered directly to site of action
- fewer systemic adverse effects
- faster response
- cheapest form of medication
- can be used with a spacer
Disadvantages of using metered dose inhalers.
- requires proper technique
- low percentage of drug reaches the lung (even with best technique, only 20% makes it to end of bronchioles or alveoli)
- inconvenience
- cold weather impairs the propellant
- utilizes a propellant - environmental impact
Steps for using a metered dose inhaler:
- Shake
- Prime - puff out 1 or 2.
- Time inhale while pushing down to get propellant to release medications.
Can be difficult in middle of exacerbation. Can be made easier with spacer.
How do breath-actuated metered dose inhalers work?
- does not use propellant
- mechanism not activated until patient inhales
- cannot use with a spacer
- more expensive than propellant based MDIs
How do dry powder inhalers work?
- drug contained in capsule or other package
- break package to allow drug to be inhaled
- patient inhales deeply and draws powdered drug into lungs
- no need to prime or shake
- substantially more expensive
- if moisture gets into the chamber, it can clog it up
Name some issues with inhalers:
- can cause coughing, which can cause medication to be coughed back out. Need to hold for a few seconds.
- must keep inhalers and spacers clean
- moisture can interfere with drug release from DPI
- cold temperatures decrease efficiency of propellant in MDIs
Goals of asthma therapy:
- prevent chronic and troublesome symptoms
- maintain normal lung function
- prevent exacerbation
- provide adequate pharmacotherapy with minimal adverse effects
How can we educate patients about asthma medications?
- quick-relief vs long-term therapies
- adherence
- use of inhalers, spacers, peak flow meters
- WADA/CCES - some of these can be banned substances. SABAs are not banned, but there is a certain level that you can have in your blood.
How can we monitor the use of asthma medication in our athletes?
- asthma symptom control
- EIB
- need to watch for athletes using inhalers without diagnosis of asthma (self managing). They may not be receiving optimal therapy
ATs need to have a specific plan for when ______ and _____ _____ are needed with asthma.
- caution
- medical action
How can ATs help in preventing asthma attacks?
- warmups in cold weather can be effective in preventing asthma or EIB
- dry > cold triggers
- don’t train or play if particularly high environmental triggers. Can take prophylactic measures.
